1. Field of the Invention
The invention relates to a release agent for removing plastics, especially polyurethane plastics from a mold. The release agent is applied to the surface of a mold in the form of a film.
2. Description of the Prior Art
As is well known, plastics are removed from closed or open molds through the use of release agents, for instance, such as tetrafluoroethylene (Teflon.RTM.), silicon or wax type, the latter often being dissolved in solvents. The release agents used up-to-date have the disadvantage that they must be removed completely from the mold after the molded part has been removed from the latter, since otherwise it is not possible to varnish the plastic surface of the molded part in the desired manner and with the necessary adhesion. This operation of removing the release agent film adhering to the surface of the plastic is very laborious and comprises vapor degreasing and post-treatment with solvent, which result in changes of the plastic surface which necessitates in turn post-treatments such as puttying and priming, which overall leads to a considerable cost increase of the finished part. On the other hand, due to the low affinity of the release agents used heretofore vis-a-vis the plastic, particularly polyurethane or polyurea plastic, a film of release agent always remains in the mold itself after the molded part is removed. The thickness of this film grows with continuous production and must be removed from time to time, thereby interrupting the production cycle. For health reasons the use of solvents which are required for the release agents known heretofore and which furthermore lengthens the cycle time of mold removal is objectionable because the solvent must evaporate after the application, so that one must frequently operate with multi-station rotary table in the production process.